Radioimmunoassay of 15-keto-13,14-dihydro-prostaglandin F2alpha: an index for inflammation via cyclooxygenase catalysed lipid peroxidation

Methods of the Analysis of Oxylipins in Biological Samples

Oxylipins are derivatives of polyunsaturated fatty acids and due to their important and diverse functions in the body, they have become a popular subject of studies. The main challenge for researchers is their low stability and often very low concentration in samples. Therefore, in recent years there have been developments in the extraction and analysis methods of oxylipins. New approaches in extraction methods were described in our previous review. In turn, the old analysis methods have been replaced by new approaches based on mass spectrometry (MS) coupled with liquid chromatography (LC) and gas chromatography (GC), and the best of these methods allow hundreds of oxylipins to be quantitatively identified. This review presents comparative and comprehensive information on the progress of various methods used by various authors to achieve the best results in the analysis of oxylipins in biological samples.

Ozone exposure effect on systemic prostaglandin F2α in rat plasma and urine may not reveal pulmonary damage through inflammation

The acute ozone induced lung injury model has been widely used to explore injury and repair processes induced by oxidant overload. The current study evaluated acute ozone exposure effects on prostaglandin F_2α (PGF_2α) in male Fischer rat plasma and urine with the hypothesis that ozone may induce an inflammatory response in the body that can be measured by the induction of PGF_2α. That might then lead to the identification of potential marker for acute lung injury through systemic inflammation. The time and dose-dependent effects of ozone exposure on the plasma and urinary levels of a major PGF_2α metabolite15-keto-dihydro-PGF_2α were determined using a radioimmunoassay. No statistically significant differences in the PGF_2α metabolite were found between the control and the experimental groups at either ozone exposure dose (2ppm and 5ppm) or any time point (2h, 7h and 16h) post exposure for plasma and at 7 different post exposure time points (between 2 and 80h) for urine. It is concluded that acute ozone exposure does not cause changes in plasma and urinary PGF_2α, and therefore their measurement in plasma and urine may not be used to reveal pulmonary inflammation and damage by ozone.

Inflammatory F2-isoprostane, prostaglandin F2α, pentraxin 3 levels and breast cancer risk: The Swedish Mammography Cohort

INTRODUCTION

Breast cancer is a common cancer among women. Identifying cellular participation of F₂-isoprostane, prostaglandin F_2α (PGF_2α) and pentraxin 3 (PTX3) in cancer we evaluated whether their prediagnostic systemic levels that originate from different inflammatory pathways were associated with breast cancer risk.

METHODS

Seventy-eight breast cancer cases diagnosed after blood collection and 797 controls from the Swedish Mammography Cohort were analysed for urinary F₂-isoprostane, PGF_2α and plasma PTX3 levels.

RESULTS

None of the biomarkers investigated were significantly associated with breast cancer risk. However, there was the suggestion of an inverse association with PTX3 with multivariable adjusted ORs (95% CI) of 0.56 (95% CI=0.29-1.06) and 0.67 (95% CI=0.35-1.28) for the second and third tertiles, respectively (p_trend=0.20). No associations were observed between F₂-isoprostane (OR=0.87; 95% CI=0.48-1.57; p_trend=0.67) and PGF_2α metabolite (OR=1.03; 95% CI=0.56-1.88; p_trend=0.91) comparing the top to bottom tertiles.

CONCLUSIONS

The systemic levels of F₂-isoprostane, PGF_2α and PTX3 witnessed in women who later developed breast cancer may not provide prognostic information regarding tumor development in spite of their known involvement in situ cellular context. These observations may indicate that other mechanisms exist in controlling cellular formation of F₂-isoprostane, PGF_2α and PTX3 and their systemic availability in breast cancer patients.

Cellular Expression of Cyclooxygenase, Aromatase, Adipokines, Inflammation and Cell Proliferation Markers in Breast Cancer Specimen

Current evidences suggest that expression of Ki67, cyclooxygenase (COX), aromatase, adipokines, prostaglandins, free radicals, β-catenin and α-SMA might be involved in breast cancer pathogenesis. The main objective of this study was to compare expression/localization of these potential compounds in breast cancer tissues with tissues collected adjacent to the tumor using immunohistochemistry and correlated with clinical pathology. The breast cancer specimens were collected from 30 women aged between 49 and 89 years who underwent breast surgery following cancer diagnosis. Expression levels of molecules by different stainings were graded as a score on a scale based upon staining intensity and proportion of positive cells/area or individually. AdipoR1, adiponectin, Ob-R, leptin, COX-1, COX-2, aromatase, PGF2α, F2-isoprostanes and α-SMA were localised on higher levels in the breast tissues adjacent to the tumor compared to tumor specimens when considering either score or staining area whereas COX-2 and AdipoR2 were found to be higher considering staining intensity and Ki67 on score level in the tumor tissue. There was no significant difference observed on β-catenin either on score nor on staining area and intensity between tissues adjacent to the tumor and tumor tissues. A positive correlation was found between COX-1 and COX-2 in the tumor tissues. In conclusion, these suggest that Ki67, COXs, aromatase, prostaglandin, free radicals, adipokines, β-catenin and α-SMA are involved in breast cancer. These further focus the need of examination of tissues adjacent to tumor, tumor itself and compare them with normal or benign breast tissues for a better understanding of breast cancer pathology and future evaluation of therapeutic benefit.

Are increased levels of systemic oxidative stress and inflammation associated with age-related cataract?

Oxidative stress and inflammation may be involved in the etiology of age-related cataract. This study is the first to investigate the association between urinary levels of 8-iso-prostaglandin F₂α (PGF₂α; as a biomarker for systemic oxidative stress in vivo) and 15-keto-dihydro-PGF₂α (as a biomarker for systemic inflammation in vivo) and risk of age-related cataract. We observed in a nested case-control study, including 258 women with incident cataract diagnosis and/or cataract extraction and 258 women without cataract, matched on age and date of urine sample collection that, women with higher levels of urinary 8-iso-PGF₂α as compared with lower levels had an increased risk of age-related cataract. There was no difference in 15-keto-dihydro-PGF₂α levels between cases and controls. Our observations lead to the hypothesis that higher systemic oxidative stress increases the risk of developing age-related cataract.

Adrenaline increases blood-brain-barrier permeability after haemorrhagic cardiac arrest in immature pigs

BACKGROUND

Adrenaline (ADR) and vasopressin (VAS) are used as vasopressors during cardiopulmonary resuscitation. Data regarding their effects on blood-brain barrier (BBB) integrity and neuronal damage are lacking. We hypothesised that VAS given during cardiopulmonary resuscitation (CPR) after haemorrhagic circulatory arrest will preserve BBB integrity better than ADR.

METHODS

Twenty-one anaesthetised sexually immature male piglets (with a weight of 24.3 ± 1.3 kg) were bled 35% via femoral artery to a mean arterial blood pressure of 25 mmHg in the period of 15 min. Afterwards, the piglets were subjected to 8 min of untreated ventricular fibrillation followed by 15 min of open-chest CPR. At 9 min of circulatory arrest, piglets received amiodarone 1.0 mg/kg and hypertonic-hyperoncotic solution 4 ml/kg infusions for 20 min. At the same time, VAS 0.4 U/kg was given intravenously to the VAS group (n = 9) while the ADR group received ADR 20 μg/kg (n = 12). Internal defibrillation was attempted from 11 min of cardiac arrest to achieve restoration of spontaneous circulation. The experiment was terminated 3 h after resuscitation.

RESULTS

The intracranial pressure (ICP) in the post-resuscitation phase was significantly greater in ADR group than in VAS group. VAS group piglets exhibited a significantly smaller BBB disruption compared with ADR group. Cerebral pressure reactivity index showed that cerebral blood flow autoregulation was also better preserved in VAS group.

CONCLUSIONS

Resuscitation with ADR as compared with VAS after haemorrhagic circulatory arrest increased the ICP and impaired cerebrovascular autoregulation more profoundly, as well as exerted an increased BBB disruption though no significant difference in neuronal injury was observed.

Kidney injury molecule (KIM)-1 is associated with insulin resistance: results from two community-based studies of elderly individuals

BACKGROUND AND OBJECTIVES

Insulin resistance has been shown to be closely associated with glomerular filtration rate and urinary albumin/creatinine ratio, even prior to the development of diabetes. Urinary kidney injury molecule 1 (KIM-1) is a novel, highly specific marker of kidney tubular damage. The role of insulin resistance in the development of kidney tubular damage is not previously reported. Thus, we aimed to investigate the associations between insulin sensitivity (assessed by HOMA) and urinary KIM-1.

DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS

Two community-based cohorts of elderly individuals were investigated: Prospective Investigation of the vasculature in Uppsala seniors (PIVUS, n=701; mean age 75 years, 52% women); and Uppsala Longitudinal Study of adult men (ULSAM, n=533; mean age 78 years).

RESULTS

Lower insulin sensitivity was associated with higher urinary KIM-1 in both cohorts after adjustments for age, BMI, blood pressure, antihypertensive treatment, glomerular filtration rate, and urinary albumin-creatinine ratio (PIVUS: regression coefficient for 1-SD higher HOMA-IR 0.11, 95% CI 0.03-0.20, p=0.009, and ULSAM: 0.13, 95% CI 0.04-0.22, p=0.007). Results were similar in individuals without diabetes, with normal kidney function and normo-albuminuria.

CONCLUSIONS

Our findings in elderly individuals support the notion that the interplay between an impaired glucose metabolism and renal tubular damage is evident even prior to the development of diabetes and overt kidney disease.

Short-term chamber exposure to low doses of two kinds of wood smoke does not induce systemic inflammation, coagulation or oxidative stress in healthy humans

Introduction:

Air pollution increases the risk of cardiovascular diseases. A proposed mechanism is that local airway inflammation leads to systemic inflammation, affecting coagulation and the long-term risk of atherosclerosis. One major source of air pollution is wood burning. Here we investigate whether exposure to two kinds of wood smoke, previously shown to cause airway effects, affects biomarkers of systemic inflammation, coagulation and lipid peroxidation.

Methods:

Thirteen healthy adults were exposed to filtered air followed by two sessions of wood smoke for three hours, one week apart. One session used smoke from the start-up phase of the wood-burning cycle, and the other smoke from the burn-out phase. Mean particle mass concentrations were 295 µg/m³ and 146 µg/m³, and number concentrations were 140 000/cm³ and 100 000/cm³, respectively. Biomarkers were analyzed in samples of blood and urine taken before and several times after exposure. Results after wood smoke exposure were adjusted for exposure to filtered air.

Results:

Markers of systemic inflammation and soluble adhesion molecules did not increase after wood smoke exposure. Effects on markers of coagulation were ambiguous, with minor decreases in fibrinogen and platelet counts and mixed results concerning the coagulation factors VII and VIII. Urinary F₂-isoprostane, a consistent marker of in vivo lipid peroxidation, unexpectedly decreased after wood smoke exposure.

Conclusions:

The effects on biomarkers of inflammation, coagulation and lipid peroxidation do not indicate an increased risk of cardiovascular diseases in healthy adults by short-term exposure to wood smoke at these moderate doses, previously shown to cause airway effects.

Involvement of inflammation in normal pregnancy

To study the role of inflammation throughout normal pregnancy and postpartum, 37 women with normal pregnancies, including normal neonatal outcome, participated. Blood and urine samples were collected from each woman at least six times during pregnancy and postpartum. Plasma levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) and urinary levels of a prostaglandin-F2α (PGF2α ) metabolite were measured. Median, 25th to 75th centile and average change per gestational week of IL-6, TNF-α and the PGF2α metabolite were measured. Levels of IL-6 increased significantly throughout pregnancy and remained high postpartum. No change in TNF-α could be seen. The PGF2α metabolite levels increased significantly throughout pregnancy and decreased postpartum. These results suggest that mild but significant inflammatory activity is involved in the development of normal pregnancy, which might have important physiological roles.

Effects of enriched environment on COX-2, leptin and eicosanoids in a mouse model of breast cancer

Cyclooxygenase-2 (COX-2) and adipokines have been implicated in breast cancer. This study investigated a possible link between COX-2 and adipokines in the development of mammary tumors. A model of environmental enrichment (EE), known to reduce tumor growth was used for a syngeneic murine model of mammary carcinoma. 3-week-old, female C57BL/6 mice were housed in standard environment (SE) or EE cages for 9 weeks and transplanted orthotopically with syngeneic EO771 adenocarcinoma cells into the right inguinal mammary fat pad. EE housing influenced mammary gland development with a decrease in COX-2 expressing cells and enhanced side-branching and advanced development of alveolar structures of the mammary gland. Tumor volume and weight were decreased in EE housed mice and were associated with a reduction in COX-2 and Ki67 levels, and an increase in caspase-3 levels. In tumors of SE mice, high COX-2 expression correlated with enhanced leptin detection. Non-tumor-bearing EE mice showed a significant increase in adiponectin levels but no change in those of leptin, F(2)-isoprostanes, PGF(2α), IL-6, TNF-α, PAI-1, and MCP-1 levels. Both tumor-bearing groups (SE and EE housing) had increased resistin, IL-6, TNF-α, PAI-1 and MCP-1 levels irrespective of the different housing environment demonstrating higher inflammatory response due to the presence of the tumor. This study demonstrates that EE housing influenced normal mammary gland development and inhibited mammary tumor growth resulting in a marked decrease in intratumoral COX-2 activity and an increase in the plasma ratio of adiponectin/leptin levels.

Inflammation, oxidative stress, glomerular filtration rate, and albuminuria in elderly men: a cross-sectional study

Background

The role of inflammation and oxidative stress in mild renal impairment in the elderly is not well studied. Accordingly, we aimed at investigating the associations between estimated glomerular filtration rate (eGFR), albumin/creatinine ratio (ACR), and markers of different inflammatory pathways and oxidative stress in a community based cohort of elderly men.

Findings

Cystatin C-based GFR, ACR, and biomarkers of cytokine-mediated inflammation (interleukin-6, high-sensitivity C-reactive protein[CRP], serum amyloid A[SAA]), cyclooxygenase-mediated inflammation (urinary prostaglandin F2α [PGF2α]), and oxidative stress (urinary F2 isoprostanes) were assessed in the Uppsala Longitudinal Study of Adult Men(n = 647, mean age 77 years).

Results

In linear regression models adjusting for age, BMI, smoking, blood pressure, LDL-cholesterol, HDL-cholesterol, triglycerides, and treatment with statins, ACE-inhibitors, ASA, and anti-inflammatory agents, eGFR was inversely associated with CRP, interleukin-6, and SAA (β-coefficient −0.13 to −0.19, p < 0.001 for all), and positively associated with urinary F2-isoprostanes (β-coefficient 0.09, p = 0.02). In line with this, ACR was positively associated with CRP, interleukin-6, and SAA (β- coefficient 0.09-0.12, p < 0.02 for all), and negatively associated with urinary F2-isoprostanes (β-coefficient −0.12, p = 0.002). The associations were similar but with lower regression coefficients in a sub-sample with normal eGFR (>60 ml/min/1.73 m2, n = 514), with the exception that F2-isoprostane and SAA were no longer associated with eGFR.

Conclusion

Our data indicate that cytokine-mediated inflammation is involved in the early stages of impaired kidney function in the elderly, but that cyclooxygenase-mediated inflammation does not play a role at this stage. The unexpected association between higher eGFR/lower albuminuria and increased F2-isoprostanes in urine merits further studies.

Effects of n-6 PUFAs compared with SFAs on liver fat, lipoproteins, and inflammation in abdominal obesity: a randomized controlled trial

BACKGROUND

Replacing SFAs with vegetable PUFAs has cardiometabolic benefits, but the effects on liver fat are unknown. Increased dietary n-6 PUFAs have, however, also been proposed to promote inflammation-a yet unproven theory.

OBJECTIVE

We investigated the effects of PUFAs on liver fat, systemic inflammation, and metabolic disorders.

DESIGN

We randomly assigned 67 abdominally obese subjects (15% had type 2 diabetes) to a 10-wk isocaloric diet high in vegetable n-6 PUFA (PUFA diet) or SFA mainly from butter (SFA diet), without altering the macronutrient intake. Liver fat was assessed by MRI and magnetic resonance proton (1H) spectroscopy (MRS). Proprotein convertase subtilisin/kexin type-9 (PCSK9, a hepatic LDL-receptor regulator), inflammation, and adipose tissue expression of inflammatory and lipogenic genes were determined.

RESULTS

A total of 61 subjects completed the study. Body weight modestly increased but was not different between groups. Liver fat was lower during the PUFA diet than during the SFA diet [between-group difference in relative change from baseline; 16% (MRI; P < 0.001), 34% (MRS; P = 0.02)]. PCSK9 (P = 0.001), TNF receptor-2 (P < 0.01), and IL-1 receptor antagonist (P = 0.02) concentrations were lower during the PUFA diet, whereas insulin (P = 0.06) tended to be higher during the SFA diet. In compliant subjects (defined as change in serum linoleic acid), insulin, total/HDL-cholesterol ratio, LDL cholesterol, and triglycerides were lower during the PUFA diet than during the SFA diet (P < 0.05). Adipose tissue gene expression was unchanged.

CONCLUSIONS

Compared with SFA intake, n-6 PUFAs reduce liver fat and modestly improve metabolic status, without weight loss. A high n-6 PUFA intake does not cause any signs of inflammation or oxidative stress. Downregulation of PCSK9 could be a novel mechanism behind the cholesterol-lowering effects of PUFAs. This trial was registered at clinicaltrials.gov as NCT01038102.

Enhanced prostaglandin F2α formation in human pregnancy and the effect of increased oily fish intake: results from the Salmon in Pregnancy Study

Oily fish intake during pregnancy may reduce the risk of allergic diseases in infancy possibly by shifts in the fatty acid balance and subsequent altered prostaglandin (PG) formation. This intervention is the first study to evaluate if increased oily fish intake affects in vivo PGF(2α) formation during pregnancy. British pregnant women were randomised to two portions of farmed salmon weekly (n=47), or maintenance of their normal diet low in fish (n=41), from pregnancy week 20 until parturition. The concentrations of eicosapentaenoic and docosahexaenoic acids in plasma phosphatidylcholine (PC) were higher and the concentration of arachidonic acid in plasma PC was lower in the salmon group than the control group at weeks 34 and 38 of pregnancy. PGF(2α) formation was evaluated by urinary measurement of 15-keto-dihydro-PGF(2α), a major PGF(2α) metabolite, at 20, 34 and 38 weeks. In both the salmon and control groups urinary 15-keto-dihydro-PGF(2α) concentrations increased significantly during pregnancy, which may be of physiological importance. Oily fish intervention altered fatty acid concentrations but did not affect urinary 15-keto-dihydro-PGF(2α) concentrations in pregnant women.

Obesity modifies the relations between serum markers of dairy fats and inflammation and oxidative stress among adolescents

Pentadecanoic acid (15:0) and heptadecanoic acid (17:0), the dairy-specific saturated fatty acids have been inversely, while inflammation and oxidative stress have been positively related to the risk of cardiovascular disease (CVD). Both fatty acid metabolism and inflammation and oxidative stress may be influenced by adiposity. In the current cross-sectional analyses among adolescents (mean age 15 years), we determined whether overweight status modified the associations between dairy fatty acids (pentadecanoic acid (15:0) and heptadecanoic acid (17:0)) represented in serum phospholipids (PL) and markers of inflammation and oxidative stress. Six biomarkers for inflammation and oxidative stress were analyzed, including circulating adiponectin, C-reactive protein (CRP), cytokines interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), and urinary 15-keto-dihydro-PGF2α (15-keto) and 8-iso-PGF2α (F2-iso). Generalized linear regression analyses, adjusted for age, gender, race, tanner score, total energy intake and physical activity, revealed that PL dairy fatty acids were inversely associated with CRP, F2-iso and 15-keto in overweight, but not in normal weight adolescents (all P(interaction) < 0.05). However, higher level of PL dairy fatty acids was associated with lower IL-6 among all adolescents. Further adjustment for dietary intake of calcium, vitamin D, protein, total flavonoids, and ω-3 fatty acids did not materially change the findings. Dairy-specific saturated fats, i.e., 15:0 and 17:0 fatty acids, may contribute to the potential health benefits of dairy products, especially for overweight adolescents.

Neuroprotective effects of 17β-estradiol after hypovolemic cardiac arrest in immature piglets: the role of nitric oxide and peroxidation

We recently reported that cerebral and cardiac injuries are mitigated in immature female piglets after severe hemorrhage with subsequent cardiac arrest. Female sex was also associated with a smaller increase in the cerebral expression of inducible nitric oxide synthase (iNOS) and neuronal nitric oxide synthase (nNOS). In the current study, we tested the hypothesis that exogenously administered 17β-estradiol (E₂) can improve neurological outcome by NOS modulation. Thirty-nine sexually immature piglets were bled to a mean arterial pressure of 35 mmHg over 15 min. Fifty micrograms per kilogram of E₂ was then administered to 10 male and 10 female animals (estradiol group), whereas control animals (n = 10 males and 9 females) received equal volume of normal saline. The animals were then subjected to ventricular fibrillation (4 min) followed by up to 15 min of open-chest cardiopulmonary resuscitation. Vasopressin 0.4 U · kg⁻¹ and amiodarone 0.5 mg · kg⁻¹ were given, and 3 mL · kg⁻¹ of 7.5% saline with 6% dextran was administered over 20 min. All surviving animals were killed after 3 h, and their brains examined for histological injury and NOS expression. No significant differences were observed in survival or hemodynamics between the groups. Compared with the control group, animals in the E₂ group exhibited a significantly smaller increase in nNOS and iNOS expression, a smaller blood-brain-barrier disruption, and a mitigated neuronal injury. There was a significant correlation between nNOS and iNOS levels and neuronal injury. Interestingly, estradiol attenuated cerebral damage (including lower activation of nNOS and iNOS) both in male and female piglets. In conclusion, in our immature piglet model of hypovolemic cardiac arrest, E₂ downregulates iNOS and nNOS expression and results in decreased blood-brain-barrier permeability disruption and smaller neuronal injury.

Propofol mitigates systemic oxidative injury during experimental cardiopulmonary cerebral resuscitation

Effects of propofol, an intravenous anesthetic agent that exerts potent antioxidant properties, were investigated in an experimental model of cardiac arrest and cardiopulmonary resuscitation. An extended cardiac arrest with 15 randomized piglets was studied to assess the effect of propofol or its solvent intralipid as the control group. Oxidative stress (as measured by a major F(2)-isoprostane) and inflammation (a major metabolite of PGF(2α)) were evaluated in addition to the hemodynamic evaluation, protein S-100β and in situ tissue brain damage by immunochemistry at sacrifice after 3h of reperfusion following cardiac arrest and restoration of spontaneous circulation (ROSC). ROSC increased jugular bulb plasma levels of F(2)-isoprostane and PGF(2α) metabolite significantly more in controls than in the propofol-treated group. In situ tissue damage after ischemia-reperfusion was variable among the pigs at sacrifice, but tended to be greater in the control than the propofol-treated group. Propofol significantly reduced an ROSC-mediated oxidative stress in the brain.

Metabolic effects of krill oil are essentially similar to those of fish oil but at lower dose of EPA and DHA, in healthy volunteers

The purpose of the present study is to investigate the effects of krill oil and fish oil on serum lipids and markers of oxidative stress and inflammation and to evaluate if different molecular forms, triacylglycerol and phospholipids, of omega-3 polyunsaturated fatty acids (PUFAs) influence the plasma level of EPA and DHA differently. One hundred thirteen subjects with normal or slightly elevated total blood cholesterol and/or triglyceride levels were randomized into three groups and given either six capsules of krill oil (N = 36; 3.0 g/day, EPA + DHA = 543 mg) or three capsules of fish oil (N = 40; 1.8 g/day, EPA + DHA = 864 mg) daily for 7 weeks. A third group did not receive any supplementation and served as controls (N = 37). A significant increase in plasma EPA, DHA, and DPA was observed in the subjects supplemented with n-3 PUFAs as compared with the controls, but there were no significant differences in the changes in any of the n-3 PUFAs between the fish oil and the krill oil groups. No statistically significant differences in changes in any of the serum lipids or the markers of oxidative stress and inflammation between the study groups were observed. Krill oil and fish oil thus represent comparable dietary sources of n-3 PUFAs, even if the EPA + DHA dose in the krill oil was 62.8% of that in the fish oil.

Effects of dietary fat modification on oxidative stress and inflammatory markers in the LIPGENE study

Subjects with the metabolic syndrome (MetS) have enhanced oxidative stress and inflammation. Dietary fat quality has been proposed to be implicated in these conditions. We investigated the impact of four diets distinct in fat quantity and quality on 8-iso-PGF2α (a major F2-isoprostane and oxidative stress indicator), 15-keto-13,14-dihydro-PGF2α (15-keto-dihydro-PGF2α, a major PGF2α metabolite and marker of cyclooxygenase-mediated inflammation) and C-reactive protein (CRP). In a 12-week parallel multicentre dietary intervention study (LIPGENE), 417 volunteers with the MetS were randomly assigned to one of the four diets: two high-fat diets (38 % energy (%E)) rich in SFA or MUFA and two low-fat high-complex carbohydrate diets (28 %E) with (LFHCC n-3) or without (LFHCC) 1·24 g/d of very long chain n-3 fatty acid supplementation. Urinary levels of 8-iso-PGF2α and 15-keto-dihydro-PGF2α were determined by RIA and adjusted for urinary creatinine levels. Serum concentration of CRP was measured by ELISA. Neither concentrations of 8-iso-PGF2α and 15-keto-dihydro-PGF2α nor those of CRP differed between diet groups at baseline (P>0·07) or at the end of the study (P>0·44). Also, no differences in changes of the markers were observed between the diet groups (8-iso-PGF2α, P = 0·83; 15-keto-dihydro-PGF2α, P = 0·45; and CRP, P = 0·97). In conclusion, a 12-week dietary fat modification did not affect the investigated markers of oxidative stress and inflammation among subjects with the MetS in the LIPGENE study.

Supplementation with fatty acids influences the airway nitric oxide and inflammatory markers in patients with cystic fibrosis

OBJECTIVES

To obtain a balance in the fatty acid (FA) metabolism is important for the inflammatory response and of special importance in cystic fibrosis (CF), which is characterized by impaired FA metabolism, chronic inflammation, and infection in the airways. Nitric oxide (NO) has antimicrobial properties and low nasal (nNO) and exhaled NO (FENO), commonly reported in CF that may affect bacterial status. The present study investigates the effect of different FA blends on nNO and FENO and immunological markers in patients with CF.

PATIENTS AND METHODS

Forty-three patients with CF and "severe" mutations were consecutively enrolled in a randomized double-blind placebo-controlled study with 3 FA blends containing mainly n-3 or n-6 FA or saturated FA acting as placebo. FENO, nNO, serum phospholipid concentrations of FA, and biomarkers of inflammation were measured before and after 3 months of supplementation.

RESULTS

Thirty-five patients in clinically stable condition completed the study. The serum phospholipid FA pattern changed significantly in all 3 groups. An increase of the n-6 FA, arachidonic acid, was associated with a decrease of FENO and nNO. The inflammatory biomarkers, erythrocyte sedimentation rate, and interleukin-8 decreased after supplementation with n-3 FA and erythrocyte sedimentation rate increased after supplementation with n-6 FA.

CONCLUSIONS

This small pilot study indicated that the composition of dietary n-3 and n-6 FA influenced the inflammatory markers in CF. FENO and nNO were influenced by changes in the arachidonic acid concentration, supporting previous studies suggesting that both the lipid abnormality and the colonization with Pseudomonas influenced NO in the airways.

Sex differences in cerebral injury after severe haemorrhage and ventricular fibrillation in pigs

BACKGROUND

Experimental studies of haemorrhagic shock have documented a superior haemodynamic response and a better outcome in female animals as compared with male controls. Such sexual dimorphism has, nevertheless, not been reported after circulatory arrest that follows exsanguination and shock. We aimed to study differences in cerebral injury markers after exsanguination cardiac arrest in pre-pubertal piglets. The hypothesis was that cerebral injury is less extensive in female animals, and that this difference is independent of sexual hormones or choice of resuscitative fluid.

METHODS

Thirty-two sexually immature piglets (14 males and 18 females) were subjected to 5 min of haemorrhagic shock followed by 2 min of ventricular fibrillation and 8 min of cardiopulmonary resuscitation, using three resuscitation fluid regimens (whole blood, hypertonic saline and dextran, or acetated Ringers' solution plus whole blood and methylene blue). Haemodynamic values, cellular markers of brain injury and brain histology were studied.

RESULTS

After successful resuscitation, female piglets had significantly greater cerebral cortical blood flow, tended to have lower S-100beta values and a lower cerebral oxygen extraction ratio. Besides, in female animals, systemic and cerebral venous acidosis were mitigated. Female piglets exhibited a significantly smaller increase in neuronal nitric oxide synthase (nNOS) and inducible nitric oxide synthase (iNOS) expression in their cerebral cortex, smaller blood-brain-barrier (BBB) disruption and significantly smaller neuronal injury.

CONCLUSION

After resuscitation from haemorrhagic circulatory arrest, cerebral reperfusion is greater, and BBB permeability and neuronal injury is smaller in female piglets. An increased cerebral cortical iNOS and nNOS expression in males implies a mechanistic relationship with post-resuscitation neuronal injury and warrants further investigation.

Effects of deep-frying oil on blood pressure and oxidative stress in spontaneously hypertensive and normotensive rats

OBJECTIVE

Ingestion of deep-frying oil has been reported to cause physiologic and histologic changes in experimental animals' tissue, increase the oxidative stress, and possibly lead to death. The purpose of this study was to investigate the effect of deep-frying oil on oxidative stress and blood pressure in spontaneously hypertensive (SHR) and Wistar Kyoto (WKY) rats.

METHODS

Deep-frying oil was prepared by frying fresh soybean oil at 180 +/- 5 degrees C for 8 h each day, for 4 consecutive days. Male SHR and WKY rats were fed diets containing 15% fresh soybean oil or deep-frying oil (DO) for 10 wk.

RESULTS

Rats ingesting the DO diet had lower feed efficiency and higher relative liver and kidney weights but deep frying had no significant influence on blood pressure in WKY or SHR rats. The DO diet had no effect on plasma renin activity, aldosterone content, or tissue angiotension-I-converting enzyme activity. WKY rats fed the DO diet showed significantly increased urinary thromboxane B(2) and 8-iso-prostaglandin F(2alpha) excretion, but not urinary 6-keto-prostaglandin F(1alpha) excretion. Diets containing deep-frying oil resulted in increased plasma thiobarbituric acid-reactive substances and nitric oxide contents and decreased plasma total antioxidant capacity in SHR and WKY rats.

CONCLUSION

The ingestion of deep-frying oil seemed not to influence blood pressure or its related parameters, but altered eicosanoid metabolism and elevated oxidative stress in SHR and WKY rats.

Serum selenium predicts levels of F2-isoprostanes and prostaglandin F2αin a 27 year follow-up study of Swedish men

Low concentrations of selenium (Se) predict mortality and cardiovascular diseases in some populations. The effect of Se on in vivo indicators of oxidative stress and inflammation, two important features of atherosclerosis, in human populations is largely unexplored. This study investigated the longitudinal association between serum selenium (s-Se) and a golden standard indicator of oxidative stress in vivo (8-iso-prostaglandin F2alpha, a major F2-isoprostane), an indicator of cyclooxygenase (COX)-mediated inflammation (prostaglandin F2alpha), high sensitive C-reactive protein (hsCRP), interleukin-6 (IL-6) and serum amyloid A protein (SAA) in a follow-up study of 27 years. The s-Se was measured in 615 Swedish men at 50 years of age in a health investigation. The status of oxidative stress and inflammation was evaluated in a re-investigation 27 years later by quantification of urinary 8-iso-PGF2alpha and 15-keto-dihydro-PGF2alpha (a major metabolite of PGF2alpha) and serum hsCRP, SAA and IL-6. Men in the highest quartile of s-Se at age 50 had decreased levels of 8-iso-PGF2alpha compared to all lower quartiles and decreased levels of PGF2alpha compared to all lower quartiles at follow-up. These associations were independent of BMI, diabetes, hyperlipidemia, hypertension, smoking, alpha-tocopherol and beta-carotene at baseline. The s-Se was not associated with hsCRP, SAA or IL-6 at follow-up. In conclusion, high concentrations of s-Se predict reduced levels of oxidative stress and subclinical COX-mediated (but not cytokine-mediated) inflammation in a male population. The associations between Se, oxidative stress and inflammation, respectively, might be related to the proposed cardiovascular protective property of Se.

Oxidative Stress and Myocardial Damage during Elective Percutaneous Coronary Interventions and Coronary AngiographyA Comparison of Blood-borne Isoprostane and Troponin Release

The role of oxidative stress in clinical cardiology is still controversial. The aims of the present study were to examine if minor ischaemic episodes as may occur during elective percutaneous coronary intervention (PCI) induce oxidative stress and, eventually, if oxygen stress correlates with myocardial injury. Thirty eight and nine patients underwent PCI and diagnostic coronary angiography, respectively. Peripheral blood was sampled at different time points for plasma analyses of: 8-iso-PGF2alpha (free radical-mediated oxidative stress); 15-keto-dihydro-PGF2alpha (cyclooxygenase-mediated inflammation); troponin-T (myocardial injury); hsCRP, vitamin A and vitamin E; and, total antioxidants status (TAS). In both groups 8-iso-PGF2alpha increased transiently by approximately 80% (p < 0.001) during the procedure. There was a minor troponin-T release (p < 0.001) after PCI, but no correlation with 8-iso-PGF2alpha. Troponin-T did not increase after angiography. 15-keto-dihydro-PGF2alpha decreased by 50% after ended procedure, but increased by 100% after 24 h compared to baseline. hsCRP increased significantly (p < 0.001) from baseline to the next day in the PCI-group, but not in the angiography group. Vitamins and TAS decreased slightly after the procedures. It is concluded that a moderate oxidative stress was induced by both elective PCI and coronary angiography but that no correlation was found between oxidative stress and myocardial injury in this setting. This indicates that other mechanisms than ischaemia-reperfusion episodes caused an elevation in plasma isoprostane such like the injury at a vascular site mutual for both procedures. A secondary finding from the study was elevated markers of early inflammatory response, not only after PCI, but also after angiography.

Glycaemic status in relation to oxidative stress and inflammation in well-controlled type 2 diabetes subjects

The aim of the present observational study was to investigate the relationships between glycaemic status and levels of oxidative stress and inflammation in well-controlled type 2 diabetes subjects. Metabolic variables (weight, BMI, waist circumference (waist), blood glucose, glycated Hb (HbA(1c)), insulin, blood lipids), biomarkers of oxidative stress (8-iso-PGF(2alpha), malondialdehyde, 8-oxo-7,8-dihydro-2'-deoxyguanosine, formamido pyrimidine glycosylase-sites, frequency of micronucleated erythrocytes, nitrotyrosine) and inflammatory markers (high sensitivity C-reactive protein (hsCRP), IL-6, cyclo-oxygenase-catalyzed PGF(2alpha)-metabolite) were measured. Fifty-six patients (thirty women and twenty-six men, age 62.3 (SD 7.0) years, HbA(1c) 6.1 (SD 0.9) %, BMI 28.3 (SD 3.8) kg/m(2), waist 99.6 (SD 11.1) cm) were included in the study. HbA(1c) (r 0.29, P=0.03) and blood glucose (r 0.33, P=0.01) correlated positively with 8-iso-PGF(2alpha). Positive correlations were also observed between HbA(1c) and nitrotyrosine (r 0.42, P=0.01), waist and hsCRP (r 0.37, P=0.005), hsCRP and IL-6 (r 0.61, P<0.0001) and between PGF(2alpha)-metabolite and 8-iso-PGF(2alpha) (r 0.27, P=0.048). The present study indicates that glycaemic status is associated with oxidative stress even in subjects with well-controlled type 2 diabetes. Furthermore, inflammation was more related to abdominal obesity than to glycaemic control. A large number of biomarkers of oxidative stress and inflammation were investigated, but only a few associations were found between the markers. This could be due to the fact that none of these biomarkers biosynthesises via similar pathways or simultaneously owing to their diverse nature and origin.

F2-isoprostane induced prostaglandin formation in the rabbit

F(2)-isoprostanes, non-enzymatic free radical mediated products of arachidonic acid, have shown to form during various oxidant stress status and have potent biological effects. This study investigates to what extent 8-iso-PGF(2alpha) (a major F(2)-isoprostane), a bioactive product of lipid peroxidation can modify endogenous prostaglandin F(2alpha) (PGF(2alpha)) formation since prostaglandins are inflammatory as well as potent vasoregulatory substances that modulate diverse important physiological functions, and also form during acute and chronic inflammation. An immediate appearance and disappearance of 8-iso-PGF(2alpha) was seen in both plasma and urine within a short interval after i.v. administration of 43 microg/kg of 8-iso-PGF(2alpha) to the rabbits. A successive but differential formation of PGF(2alpha) resulted in a rapid and pulsatile increase of plasma 15-keto-dihydro-PGF(2alpha), a major metabolite of primary PGF(2alpha). Later, this compound was excreted efficiently as intact compound into the urine during the 3 h of experiment. A 8-fold increase of PGF(2alpha) metabolite in plasma at 10 min and 12-fold increase in the urine at 30-60 after the i.v. administration of 8-iso-PGF(2alpha) was observed which continued throughout the 3 h of experiment. This observation suggests that pharmacologically administered or endogenously produced 8-iso-PGF(2alpha) during oxidant stress induces prostaglandin formation presumably through the classical cyclooxygenase-catalysed arachidonic acid oxidation which might be inflammatory itself to the cells and exerts further vasoconstrictive effects.

F(2)-isoprostanes as novel biomarkers for type 2 diabetes: a review

Oxidative stress (OS) has been implicated as one of the major underlying mechanisms behind many acute and chronic diseases. However, the measurement of free radicals or their end products is complicated. Isoprostanes, derived from the non-enzymatic peroxidation of arachidonic acid are now considered to be reliable biomarkers of oxidant stress in the human body. Isoprostanes are involved in many of the human diseases such as type 2 diabetes. In type 2 diabetes elevated levels of F₂-Isoprostanes (F₂-IsoPs) have been observed. The measurement of bioactive F₂-IsoPs levels offers a unique noninvasive analytical tool to study the role of free radicals in physiology, oxidative stress-related diseases, and acute or chronic inflammatory conditions. Measurement of oxidative stress by various other methods lacks specificity and sensitivity. This review aims to shed light on the implemention of F₂-IsoPs measurement as a gold-standard biomarker of oxidative stress in type 2 diabetics.

Fruit and vegetable consumption and its relation to markers of inflammation and oxidative stress in adolescents

BACKGROUND

Fruits and vegetables, foods rich in flavonoids and antioxidants, have been associated with lower risk of stroke, coronary heart disease, and markers of inflammation and oxidative stress in adults. Markers of inflammation and oxidative stress are predictors of coronary heart disease risk; however, it is unknown whether these markers are related to dietary flavonoid and antioxidant intake in youth.

OBJECTIVE

To determine whether greater intakes of fruit and vegetables, antioxidants, folate, and total flavonoids were inversely associated with markers of inflammation and oxidative stress in 285 adolescent boys and girls aged 13 to 17 years.

DESIGN

In this cross-sectional study conducted between February 1996 and January 2000, diet was assessed by a 127-item food frequency questionnaire. Height and weight measurements were obtained and a fasting blood sample drawn. Spearman partial correlation analyses evaluated the relation of intakes of fruit and vegetables, antioxidants, folate, and flavonoids with markers of inflammation (C-reactive protein, interleukin-6, tumor necrosis factor-alpha, and 15-keto-dihydro-PGF(2alpha) metabolite and oxidative stress (urinary 8-iso prostaglandin F(2alpha), an F(2)-isoprostane), adjusting for age, sex, race, Tanner stage, energy intake, and body mass index.

RESULTS

Urinary F(2)-isoprostane was inversely correlated with intakes of total fruit and vegetables, vitamin C, beta carotene, and flavonoids. Serum C-reactive protein was significantly inversely associated with intakes of fruit (r=-0.19; P=0.004), vitamin C (r=-0.13, P=0.03), and folate (r=-0.18; P=0.004). Serum interleukin-6 was inversely associated with intakes of legumes, vegetables, beta carotene, and vitamin C. Serum tumor necrosis factor-alpha was inversely associated with beta carotene (r=-0.14, P=0.02) and luteolin (r=-0.15, P=0.02).

CONCLUSION

Study results show that the beneficial effects of fruit and vegetable intake on markers of inflammation and oxidative stress are already present by early adolescence and provide support for the Dietary Guidelines for Americans "to consume five or more servings per day" of fruits and vegetables to promote beneficial cardiovascular health.

Long-term moderate intervention with n-3 long-chain PUFA-supplemented dairy products: effects on pathophysiological biomarkers in patients with rheumatoid arthritis

n-3 long-chain PUFA (n-3 LC-PUFA) may improve cardiovascular and inflammatory diseases. The effects of n-3 LC-PUFA-supplemented dairy products on inflammation and immunological parameters, biomarkers of oxidative stress, serum lipids, and on disease activity were determined in patients with rheumatoid arthritis (RA). Forty-five subjects (forty-three females and two males) were randomly divided into two groups in a double-blind, placebo-controlled cross-over study. Both groups received placebo or verum products consecutively for 3 months with a 2-month washout phase between the two periods. Blood samples were taken at the beginning and at the end of each period. The dairy products generally improved serum lipids by increasing HDL and lowering lipoprotein a. The n-3 LC-PUFA supplements act to lower TAG. Additionally, a decreased lipopolysaccharide-stimulated cylo-oxygenase-2 expression was found in patients who had consumed the enriched dairy products. The majority of the CD analysed were not influenced, although n-3 LC-PUFA did suppress the immune response as lymphocytes and monocytes were found to be significantly decreased. The n-3 LC-PUFA did not increase the biomarkers of oxidative stress such as 8-iso-PGF(2alpha) and 15-keto-dihydro PGF(2alpha), and DNA damage like 7,8-dihydro-8-oxo-2'-deoxyguanosine. The long-term consumption of dairy products (2 x 12 weeks) diminished the excretion of hydroxypyridinium crosslinks, and favoured the diastolic blood pressure. The consumption of moderate doses of n-3 LC-PUFA in combination with dairy products did not improve the disease activity. However, there is evidence of cardioprotective effects. Furthermore, the long-term consumption of dairy products acts against the cartilage and bone destruction in RA.

A polymorphism in the cyclooxygenase 1 gene is associated with decreased inflammatory prostaglandin F2alpha formation and lower risk of cardiovascular disease

This study investigates the impact of genetic variation in the cyclooxygenase-1 (COX-1) gene on formation of the vasoconstrictive, pro-inflammatory prostaglandin F(2)(alpha) (PGF(2)(alpha)) and development of cardiovascular disease (CVD). We determined COX-1 genotypes, PGF(2)(alpha) formation and CVD prevalence in a Swedish cohort of 809 men at age 77 years. Of these, 237 had a history of CVD according to the registry data. Four of nine COX-1 single nucleotide polymorphisms were associated with altered formation of PGF(2)(alpha) (P<0.05). Two COX-1 gene variants (rs10306135 and rs883484) remained significantly associated with altered PGF(2)(alpha) formation after adjusted significance level for multiple testing (alpha-level=0.0059). Furthermore, individuals homozygote for the variant allele rs10306135 had lower prevalence of CVD, compared to the common allele (0% versus 30%, P=0.0047). In conclusion, subjects homozygote for the variant allele of a COX-1 gene polymorphism represent a subpopulation of men with decreased PGF(2)(alpha) formation and lower prevalence of CVD.

Low dietary intake of β-carotene, α-tocopherol and ascorbic acid is associated with increased inflammatory and oxidative stress status in a Swedish cohort

Fruit and vegetable consumption has been associated with a reduced risk of several diseases including CVD. A part of these effects seen could be linked to anti-inflammatory and antioxidative effects, although this has not been thoroughly investigated. The present study was designed to investigate the effects of the dietary intake of β-carotene, α-tocopherol and ascorbic acid on in vivo biomarkers of inflammation (PGF2α, high-sensitive C-reactive protein (hsCRP) and IL-6 formation) and oxidative stress (F2-isoprostane formation), the two important factors associated with accelerated atherosclerosis. The dietary intake of 704 participants in the Uppsala Longitudinal Study of Adult Men (ULSAM) at age 70 years was registered and inflammatory and oxidative stress biomarkers were quantified 7 years later. The registered dietary intakes of ascorbic acid and α-tocopherol were negatively associated linearly and in quartiles with both PGF2α, hsCRP, IL-6 and F2-isoprostanes, where ascorbic acid intake generally was more strongly associated. Dietary intake of β-carotene was only significantly negatively associated with F2-isoprostanes. In conclusion, the present study is the first to suggest that the intake of food rich in antioxidants is associated with reduced cyclo-oxygenase- and cytokine-mediated inflammation and oxidative stress at 7 years of follow-up. These associations could be linked to the beneficial effects of fruit and vegetables observed on CVD.

Experimental Exposure to Wood-Smoke Particles in Healthy Humans: Effects on Markers of Inflammation, Coagulation, and Lipid Peroxidation

Particulate air pollution is known to increase cardiovascular morbidity and mortality. Proposed mechanisms underlying this increase include effects on inflammation, coagulation factors, and oxidative stress, which could increase the risk of coronary events and atherosclerosis. The aim of this study was to examine whether short-term exposure to wood smoke affects markers of inflammation, blood hemostasis, and lipid peroxidation in healthy humans. Thirteen subjects were exposed to wood smoke and clean air in a chamber during two 4-h sessions, 1 wk apart. The mass concentrations of fine particles at wood smoke exposure were 240-280 mug/m3, and number concentrations were 95,000-180,000/cm3. About half of the particles were ultrafine (< 100 nm). Blood and urine samples were taken before and after the experiment. Exposure to wood smoke increased the levels of serum amyloid A, a cardiovascular risk factor, as well as factor VIII in plasma and the factor VIII/von Willebrand factor ratio, indicating a slight effect on the balance of coagulation factors. Moreover, there was an increased urinary excretion of free 8-iso-prostaglandin2alpha, a major F2-isoprostane, though this was based on nine subjects only, indicating a temporary increase in free radical-mediated lipid peroxidation. Thus, wood-smoke particles at levels that can be found in smoky indoor environments seem to affect inflammation, coagulation, and possibly lipid peroxidation. These factors may be involved in the mechanisms whereby particulate air pollution affects cardiovascular morbidity and mortality. The exposure setup could be used to establish which particle characteristics are critical for the effects.

Neuro- and cardioprotective effects of blockade of nitric oxide action by administration of methylene blue

Methylene blue (MB), generic name methylthioninium (C(16)H(18)ClN(3) S . 3H(2)O), is a blue dye synthesized in 1876 by Heinrich Caro for use as a textile dye and used in the laboratory and clinically since the 1890s, with well-known toxicity and pharmacokinetics. It has experimentally proven neuroprotective and cardioprotective effects in a porcine model of global ischemia-reperfusion in experimental cardiac arrest. This effect has been attributed to MB's blocking effect on nitric oxide synthase and guanylyl cyclase, the latter blocking the synthesis of the second messenger of nitric oxide. The physiological effects during reperfusion include stabilization of the systemic circulation without significantly increased total peripheral resistance, moderately increased cerebral cortical blood flow, a decrease of lipid peroxidation and inflammation, and less anoxic tissue injury in the brain and the heart. The last two effects are recorded as less increase in plasma concentrations of astroglial protein S-100beta, as well as troponin I and creatine kinase isoenzyme MB, respectively.

F2-isoprostane, inflammation, cardiac function and oxygenation in the endotoxaemic pig

Prostaglandins are profoundly involved in endotoxaemic shock. Twenty pigs were given endotoxin at various doses (0.063-16 microg kg(-1) h(-1)). Three non-endotoxaemic pigs served as controls. Two eicosanoids were measured in plasma (8-iso-PGF(2alpha), a free radical-mediated lipid peroxidation product, and 15-keto-dihydro-PGF(2alpha) a major metabolite of COX activity) and evaluated against the pathophysiological responses that occur during endotoxaemic shock. Endotoxin mediates an increase in both 8-iso-PGF(2alpha) and 15-keto-dihydro-PGF(2alpha). An increase in the endotoxin dose induced significant log-linear responses in 8-iso-PGF(2alpha) and 15-keto-dihydro-PGF(2alpha). Oxidative injury correlated to the TNF-alpha, IL-6, reductions in cardiac performance and to oxygen delivery and utilisation. COX-mediated inflammatory responses correlated to TNF-alpha, IL-6 and to reductions in arterial oxygen tension. Thus, oxidative injury and COX-mediated inflammation play a central role in the manifestation of endotoxaemic shock. Furthermore, formation of these eicosanoids on endotoxin-mediated alterations in pulmonary hypertension, oxygen delivery and oxygen utilisation seems to be independent of the administered endotoxin dose.

Immunological and metabolic effects of cis-9, trans-11-conjugated linoleic acid in subjects with birch pollen allergy

Animal studies suggest that conjugated linoleic acid (CLA) may modulate the immune response, while studies in healthy human subjects have shown little effect and results are controversial. However, the effects of CLA may be more prominent in situations of immune imbalance, such as allergy. We studied the effects of the natural CLA isomer, cis-9, trans-11-CLA, on allergy symptoms and immunological parameters in subjects with birch pollen allergy. In a randomised, placebo-controlled study, forty subjects (20-46 years) with diagnosed birch pollen allergy received 2 g CLA/d in capsules, which contained 65.3 % cis-9, trans-11-CLA and 8.5 % trans-10, cis-12-CLA (n 20), or placebo (high-oleic acid sunflower-seed oil) (n 20) for 12 weeks. The supplementation began 8 weeks before the birch pollen season and continued throughout the season. Allergy symptoms and use of medication were recorded daily. Lymphocyte subsets, cytokine production, immunoglobulins, C-reactive protein, lipid and glucose metabolism and lipid peroxidation were assessed before and after supplementation. The CLA group reported a better overall feeling of wellbeing (P < 0.05) and less sneezing (P < 0.05) during the pollen season. CLA supplementation decreased the in vitro production of TNF-alpha (P < 0.01), interferon-gamma (P < 0.05) and IL-5 (P < 0.05). Total plasma IgE and birch-specific IgE concentrations did not differ between groups, whereas plasma IgA (P < 0.05), granulocyte macrophage colony-stimulating factor (P < 0.05) and eosinophil-derived neurotoxin (P < 0.05) concentrations were lower after CLA supplementation. Urinary excretion of 8-iso-PGF2alpha, a major F2-isoprostane (P < 0.01), and 15-keto-dihydro-PGF2alpha, a primary PGF2alpha metabolite (P < 0.05), increased in the CLA group. The results suggest that cis-9, trans-11-CLA has modest anti-inflammatory effects in allergic subjects.

Cardio-cerebral and metabolic effects of methylene blue in hypertonic sodium lactate during experimental cardiopulmonary resuscitation

BACKGROUND

Methylene blue (MB) administered with a hypertonic-hyperoncotic solution reduces the myocardial and cerebral damage due to ischaemia and reperfusion injury after experimental cardiac arrest and also increases short-term survival. As MB precipitates in hypertonic sodium chloride, an alternative mixture of methylene blue in hypertonic sodium lactate (MBL) was developed and investigated during and after cardiopulmonary resuscitation (CPR).

METHODS

Using an experimental pig model of cardiac arrest (12 min cardiac arrest and 8 min CPR) the cardio-cerebral and metabolic effects of MBL (n=10), MB in normal saline (MBS; n=10) or in hypertonic saline dextran (MBHSD; n=10) were compared. Haemodynamic variables and cerebral cortical blood flow (CCBF) were recorded. Biochemical markers of cerebral oxidative injury (8-iso-PGF2alpha), inflammation (15-keto-dihydro-PGF2alpha), and neuronal damage (protein S-100beta) were measured in blood from the sagittal sinus, whereas markers of myocardial injury, electrolytes, and lactate were measured in arterial plasma.

RESULTS

There were no differences between groups in survival, or in biochemical markers of cerebral injury. In contrast, the MBS group exhibited not only increased CKMB (P<0.001) and troponin I in comparison with MBHSD (P=0.019) and MBL (P=0.037), but also greater pulmonary capillary wedge pressure 120 min after return of spontaneous circulation (ROSC). Lactate administration had an alkalinizing effect started 120 min after ROSC.

CONCLUSIONS

Methylene blue in hypertonic sodium lactate may be used against reperfusion injury during experimental cardiac arrest, having similar effects as MB with hypertonic saline-dextran, but in addition better myocardial protection than MB with normal saline. The neuroprotective effects did not differ.

Novel cyclooxygenase-catalyzed bioactive prostaglandin F2alpha from physiology to new principles in inflammation

Prostaglandin F2alpha (PGF2alpha), a foremost stable vasoactive cyclooxygenase (COX)-catalyzed prostaglandin, regulates a number of key physiological functions such as luteolysis, ovarian function, luteal maintenance of pregnancy, and parturition as a constitutive part of ongoing reproductive processes of the body. It has recently been implicated in the regulation of intricate pathophysiological processes, such as acute and chronic inflammation, cardiovascular and rheumatic diseases. Since the discovery of a second isoform of COXs, it has been shown that PGF2alpha can be formed in vivo from arachidonic acid through both isoforms of COXs, namely cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2). Being synthesized in various parts of the body, it metabolizes instantly to a number of rather inactive metabolites mainly in the lungs, liver, kidney, and efficiently excretes into the urine. 15-Keto-dihydro-PGF2alpha, a major stable metabolite of PGF2alpha that reflects in vivo PGF2alpha biosynthesis, is found in larger quantities than its parent compound in the circulation and urine in basal physiological conditions, with short-lived pulses during luteolysis, induced termination of pregnancy and parturition, and is increased in tissues and various body fluids during acute, sub-chronic, and severe chronic inflammation. Further, the close relationship of PGF2alpha with a number of risk factors for atherosclerosis indicates its major role in inflammation pathology. This review addresses multiple aspects of PGF2alpha in addition to its emerging role in physiology to inflammation.

Oxidative stress during coronary artery bypass operations: importance of surgical trauma and drug treatment

OBJECTIVE

To investigate oxidative stress and myocardial injury at different stages of coronary artery bypass grafting (CABG).

DESIGN

Twenty patients underwent CABG with use of cardiopulmonary bypass (CPB) and with intermittent sampling of plasma and urine. Main markers were: 8-iso-PGF2alpha (oxidative stress); troponin T (myocardial injury); and 15-keto-dihydro-PGF2alpha and hsCRP (inflammation).

RESULTS

Plasma 8-iso-PGF2alpha increased after start of surgery, but there was no further rise during CPB or after aortic cross-clamp release and no significant myocardial arterio-venous differences. An increase in troponin T was seen early after the operation, but no relationship was established between 8-iso-PGF2alpha and troponin T. 8-iso-PGF2alpha levels were elevated by preoperative withdrawal of acetylsalicylic acid (ASA) but reduced by intraoperative use of heparin. 15-keto-dihydro-PGF2alpha was elevated during operation and hsCRP following operation.

CONCLUSIONS

In the present study oxidative stress was multifactorial in origin with main impacts from surgical trauma, less from CPB and little if any from myocardial ischemia-reperfusion events. In addition, cardiovascular drugs in common use like ASA and heparin seemed to influence the pro- and antioxidant balance, a finding that has to be confirmed in future studies.

Maintaining nitric oxide-induced airway relaxation with superoxide dismutase

BACKGROUND

We have previously shown that the protective effect of inhaled nitric oxide (iNO) against methacholine-induced bronchoconstriction is negated in airways subjected to hyperosmotic stress. In this study, hypothesizing that the impaired efficiency of iNO was caused by release of reactive oxygen radicals, we examined the effect of the radical scavenging enzyme superoxide dismutase (SOD).

METHODS

Hemodynamic and respiratory measurements were performed on anesthetized rabbits after (1) inhalation of methacholine (MCh), (2) iNO (80ppm), followed by MCh, (3) inhalation of hypertonic saline (HS), followed by iNO and MCh and (4) pre-treatment with inhalation of SOD, followed by HS, iNO and MCh. We analyzed plasma for a marker of oxidative stress, 8-iso-prostaglandin (PG)F(2alpha) and for a marker of activation of COX-mediated inflammatory cascades, PGF(2alpha) metabolite.

RESULTS

Pre-treatment with SOD restored the bronchoprotective response to iNO in hyperosmotic airways. No direct effect was seen by SOD treatment on levels of 8-iso-PGF(2alpha), but this marker of oxidative stress correlated positively with increased bronchoconstriction. Hyperosmotic challenge elevated levels of PGF(2alpha) metabolite, and pre-treatment with SOD protected against this activation of the inflammatory cascade.

CONCLUSION

SOD pre-treatment restores the relaxant effects of iNO in hyperosmotically challenged airways by attenuating oxidative stress and activation of COX-mediated inflammatory cascades.

Both cyclooxygenase- and cytokine-mediated inflammation are associated with carotid intima–media thickness

BACKGROUND

Common carotid artery intima-media thickness (CCA-IMT) is a valid index of atherosclerosis, which is viewed as an inflammatory disease. It is unknown if various modes of inflammation (cyclooxygenase [COX]-mediated, cytokine-mediated), oxidative stress and anti-oxidants are independently related to CCA-IMT.

METHODS AND RESULTS

We investigated cross-sectional relations between CCA-IMT measured by B-mode ultrasound and COX-mediated inflammation (as measured by 15-keto-dihydro-prostaglandin F(2alpha) [PGF(2alpha)], cytokine-mediated inflammation (interleukin-6 [IL-6], high sensitivity C-reactive protein [hsCRP] and serum amyloid A protein [SAA]), oxidative stress (8-iso-PGF(2alpha), an F(2)-isoprostane; a non-enzymatic, free radical-induced product of arachidonic acid), and tocopherols (anti-oxidants) in a small subset of a population-based sample of elderly men (n=234) stating no use of anti-inflammatory medications. In a backward-stepwise regression analysis of correlates of CCA-IMT (with PGF(2alpha), hsCRP, IL-6, SAA, F(2)-isoprostanes, tocopherols, diabetes, body mass index (BMI), beta-blocker, statin treatment, smoking, hypertension and cholesterol), PGF(2alpha), CRP, beta-blocker treatment, diabetes and BMI were independently associated with CCA-IMT. There were no associations between F(2)-isoprostanes or tocopherols and CCA-IMT in this study.

CONCLUSION

This study suggests both COX- and cytokine-mediated inflammation to be independently associated with increased CCA-IMT, implying that there might be more than one mode of inflammation involved in atherogenesis.

Effects of plant sterol and stanol ester consumption on lipid metabolism, antioxidant status and markers of oxidative stress, endothelial function and low-grade inflammation in patients on current statin treatment

OBJECTIVE

The present study was designed to examine for the first time, side-by-side, the effects of plant sterol and stanol consumption on lipid metabolism and markers of antioxidant status, oxidative stress, endothelial dysfunction and low-grade inflammation in subjects on stable statin-treatment.

DESIGN

Double-blind, randomized, placebo-controlled, intervention trial.

SETTING

University.

SUBJECTS

Forty-five patients on current statin treatment were recruited via newspaper advertisements. Data of 41 patients were used in statistical analysis.

INTERVENTION

Subjects consumed margarine with no added plant sterols or stanols for 4 weeks and were then divided into three groups of 15 subjects. For the next 16 weeks, one group continued with the control margarine and the other two groups with either a plant sterol- or stanol (2.5 g/day)-enriched margarine. Blood was sampled at the end of the run-in and intervention periods.

RESULTS

Plant sterol and stanol consumption significantly (P=0.026) reduced low-density lipoprotein (LDL) cholesterol by 0.34 mmol/l (95% confidence interval (CI), -0.67 to -0.04 mmol/l). No effects were shown on enzymatic and non-enzymatic antioxidants and markers of oxidative modification of lipids and DNA. In addition, no effect was found on soluble adhesion molecules, C-reactive protein and monocyte chemotactic protein-1 concentrations.

CONCLUSIONS

We conclude that 16 weeks of plant sterol or stanol consumption did not affect markers of antioxidant status, oxidative stress, endothelial dysfunction and low-grade inflammation in patients on stable statin treatment, despite a significant reduction of LDL cholesterol.

Increased isoprostane and prostaglandin are prominent in neurons in Alzheimer disease

BACKGROUND

Inflammation and oxidative stress are both involved in the pathogenesis of Alzheimer disease and have been shown to be reciprocally linked. One group of molecules that have been directly associated with inflammation and the production of free radicals are the prostaglandin 13,14-dihydro 15-keto PGF2alpha and the isoprostane 8-iso-PGF2alpha.

RESULTS

To further delineate the role of inflammatory and oxidative parameters in Alzheimer disease, in this study we evaluated the amount and localization of 13,14-dihydro 15-keto PGF2alpha and 8-iso-PGF2alpha in hippocampal post mortem tissue samples from age-matched Alzheimer disease and control patients. Our results demonstrate increased levels of 13,14-dihydro 15-keto PGF2alpha and 8-iso-PGF2alpha in the hippocampal pyramidal neurons of Alzheimer disease patients when compared to control patients.

CONCLUSION

These data not only support the shared mechanistic involvement of free radical damage and inflammation in Alzheimer disease, but also indicate that multiple pathogenic "hits" are likely necessary for both the development and propagation of Alzheimer disease.